rvupgradestore.com Composet Products Fridge Defend
RV Life Magazine RV Park Reviews RV Trip Wizard

Author Topic: Onan quiet diesel 7.5 trouble code 15  (Read 332 times)

Captain154

  • Posts: 4
Onan quiet diesel 7.5 trouble code 15
« on: June 24, 2018, 09:42:12 PM »
Need help please. I have a 1999 Monaco diplomat with a onan 7.5 quiet diesel. The generator will start up but dies after just a few seconds. Shows a code 15.   Has anyone ever had this problem before? Thanks in advance.

elgarc

  • Posts: 3
Re: Onan quiet diesel 7.5 trouble code 15
« Reply #1 on: June 24, 2018, 10:00:08 PM »
You may already know what the code means, but just to make sure I'll tell you what the troubleshooting manual says:

INVERTER UNDERFREQUENCY FAULT - CODE NO 15

CORRECTIVE ACTION:
1.  Reduce the number of connected appliances, especially when A/C and battery chargers are running.
2.  Have A/C and other appliances checked for proper operation. (A locked compressor rotor can cause very low power factor.)

Beyond that, I cannot help.  Just had my code 36 repaired by Cummins.  A filter I didn't know existed and located on the 'rail' was clogged.

2005 Tiffin Allegro Bus TSP40
Toad: 2015 Jeep Cherokee Trail Hawk
Full-Time since 1991

elgarc

  • Posts: 3
Re: Onan quiet diesel 7.5 trouble code 15
« Reply #2 on: June 24, 2018, 10:03:25 PM »
After I posted above, I realized that there could be more than one code.  Did you check for that?
2005 Tiffin Allegro Bus TSP40
Toad: 2015 Jeep Cherokee Trail Hawk
Full-Time since 1991

Captain154

  • Posts: 4
Re: Onan quiet diesel 7.5 trouble code 15
« Reply #3 on: June 25, 2018, 08:01:42 AM »
Thanks, that is the only code showing, I have tried with everything off and with the main breaker off at the generator itself, but had same results

Gary RV_Wizard

  • Forum Staff
  • ---
  • *
  • Posts: 64398
  • RVer Emeritus
Re: Onan quiet diesel 7.5 trouble code 15
« Reply #4 on: June 25, 2018, 10:03:07 AM »
The Onan advice only addresses external causes, but there are internal possibilities as well.  The inverter in the Onan 7500 relies on DC power produced by the diesel engine plus DC generator, and inadequate power there can cause the inverter to malfunction, making power that is not the 60 Hz frequency it should be. May also be under voltage if that happens.   A faulty inverter module is another possibility (expensve!).  I'm pretty sure there is nothing you can do to fix this, so professional help will be needed.
Gary
--------------
Gary Brinck
Summers: Black Mountain, NC
Home: Ocala National Forest, FL

Utclmjmpr

  • ---
  • Posts: 3341
Re: Onan quiet diesel 7.5 trouble code 15
« Reply #5 on: June 26, 2018, 07:30:32 PM »
 Did you check for a second tier code??>>>Dan
38' American Tradition 38TT/330 turbo Cummins
Jeep liberty 4 down
72 VW Baja 4 down
Cedar City, Utah
USAF vet. 59-63
The difference between intelligence & stupidity is: intelligence has it's limits
      Albert Einstein.

Gary RV_Wizard

  • Forum Staff
  • ---
  • *
  • Posts: 64398
  • RVer Emeritus
Re: Onan quiet diesel 7.5 trouble code 15
« Reply #6 on: June 26, 2018, 07:34:15 PM »
15 is a second level code. The primary code would have to be a 3 in order to get the the secondary 15. There is no primary 15 on the 7500 series genset.
Gary
--------------
Gary Brinck
Summers: Black Mountain, NC
Home: Ocala National Forest, FL

Utclmjmpr

  • ---
  • Posts: 3341
Re: Onan quiet diesel 7.5 trouble code 15
« Reply #7 on: June 26, 2018, 07:35:52 PM »
 I made the classic mistake, about nine years ago , of shutting off the generator without shedding the heavy loads first.  A $1400.00 mistake I haven't made since.. Had to have the inverter replaced at a local Cummins shop.>>>Dan
38' American Tradition 38TT/330 turbo Cummins
Jeep liberty 4 down
72 VW Baja 4 down
Cedar City, Utah
USAF vet. 59-63
The difference between intelligence & stupidity is: intelligence has it's limits
      Albert Einstein.